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UPSC / UPPSC Geography Optional

Paper–II (Indian Geography) – Page 5

Climate of India – The Monsoon System

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1. Introduction

The climate of India is primarily governed by the monsoon system. Monsoon refers to the seasonal reversal of winds associated with changes in temperature and pressure. The Indian monsoon exerts a profound influence on agriculture, water resources, economy and overall life in the country.

2. Salient Features of Indian Climate

• Seasonal reversal of winds
• Concentration of rainfall in a few months
• High spatial and temporal variability
• Strong influence of relief and distance from sea

3. Origin of the Monsoon

The origin of the Indian monsoon is explained through multiple complementary theories.

A. Thermal Theory

According to this theory, intense heating of the Indian subcontinent during summer creates a low-pressure area, drawing in moisture-laden winds from the oceans.

B. Dynamic Theory

This theory emphasises the role of shifting pressure belts, especially the northward movement of the Inter-Tropical Convergence Zone (ITCZ).

C. Jet Stream Theory

The onset and withdrawal of monsoon are influenced by the position of subtropical westerly and tropical easterly jet streams.

Exam Tip: Mention ITCZ + Jet Stream for high-value answers.

4. Mechanism of Indian Monsoon

South-West Monsoon

• Onset in early June
• Arabian Sea Branch
• Bay of Bengal Branch
• Responsible for nearly 75% of annual rainfall

North-East Monsoon

• Occurs during October–December
• Affects Tamil Nadu and south-east coast
• Associated with retreating monsoon

5. Distribution of Rainfall in India

• Heavy rainfall on Western Ghats and North-East India
• Moderate rainfall in Indo-Gangetic Plains
• Low rainfall in Rajasthan and Ladakh

6. Monsoon Variability

• Early or delayed onset
• Breaks in monsoon
• Spatial variability

Factors influencing variability include ENSO, IOD and Madden–Julian Oscillation.

7. Significance of Monsoon

• Determines agricultural output
• Recharges rivers and groundwater
• Influences hydropower generation
• Supports biodiversity

8. Problems Associated with Monsoon

• Droughts due to weak monsoon
• Floods due to excessive rainfall
• Crop failure and food insecurity
• Economic instability

9. Answer Writing Strategy

• Start with a simple India rainfall map
• Explain origin using ITCZ and jet streams
• Divide mechanism into SW and NE monsoon
• Conclude with climate change perspective

Golden Rule: Diagram + mechanism + impact = top marks

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End of Geography Optional – Paper II | Page 5
Shaktimatha 369 Learning